Highly oriented pyrolytic graphite oxidation

Because STM measures a quantum-mechanical tunneling current, the tip must be within a few A of a conducting surface. Therefore any surface oxide or other contaminant will complicate operation under ambient conditions. Nevertheless, a great deal of work has been done in air, liquid, or at low temperatures on inert surfaces. Studies of adsorbed molecules on these surfaces (for example, liquid crystals on highly oriented, pyrolytic graphite ) have shown that STM is capable of even atomic resolution on organic materials. 

The actual utility of this discovery depends on the ability to go from hosts consisting of expensive, highly oriented, pyrolytic graphite to hosts composed of cheap graphite powders or fibers. Care must be taken on intercalation, because defects in such low-rank graphites may affect not only the intrinsic conductivity of the host (Z4) but may also serve as sites for oxidative reactions that may disrupt the host (Ell). 

Mazur et al. described the organization of vanadyl oxide 2,9,16,23-tetraphenoxy-29H, 31//-phthalocyanine (V02+PcPhO) on highly oriented pyrolytic graphite (HOPG) [47], They focused on the fact that the adsorption geometry of nonplanar Pc complexes of titanyl and vanadyl (TiOPc and VOPc) is not well understood... 

STM and STS measurements have been also performed on B-doped and undoped SiNWS [45] produced by OAG [23, 80]. The as-grown sample consisted primarily of SiNWs and nanoparticle chains coated with an oxide sheath. Samples for STM and STS measurements were prepared by dispersing the SiNWs into a suspension, which was then spin-coated onto highly oriented pyrolytic graphite (HOPG) substrates. The presence of nanoparticle chains and nanowires in the B-doped SiNWs sample was observed. Clear and regular nanoscale domains were observed on the SiNW surface, which were attributed to B-induced surface recon-... 

Gewirth, A.A. and Bard, A.J. (1988). In situ scanning tunnehng microscopy of the anodic oxidation of highly oriented pyrolytic graphite surfaces. J. Phys. Chem., 92, 55663-6. 

The manufacture of heterogeneous catalysts from pre-prepared nanometal colloids as precursors via the so-called precursor concept ll has attracted industrial inter-est.l l An obvious advantage of the new mode of preparation compared with the conventional salt-impregnation method is that both the size and the composition of the colloidal metal precursors can be tailored for special applications independently of the support. In addition, the metal particle surface can be modified by lipophilic or hydrophilic protective shells, and covered with intermediate layers, e.g. of oxide. The addition of dopants to the precursor is also possible. The second step of the manufacture of the catalyst consists in the simple adsorption of the pre-prepared particles by dipping the supports into organic or aqueous precursor solutions at ambient temperature. This has been demonstrated, e.g., for charcoal, various oxidic support materials, even low-surface materials such as quartz, sapphire, and highly oriented pyrolytic graphite. A subsequent calcination step is not required (see Fig. 1). 

Fan F-RF, Park S, Zhu Y, Ruoff RS, Bard AJ (2008) Electrogenerated chemiluminescence of partially oxidized highly oriented pyrolytic graphite surfaces and of graphene oxide nanoparticles. J Am Chem Soc 131(3) 937-939... 

For coreactant ECL studies, e.g., in aqueous Ru(bpy)3 /TPrA solution, degassing is often unneeded. Thus, Fisherbrand glass tooled-neck vials (www.fishersci.com) are frequently used as ECL cells. When ECL experiments are carried out at a wafer-type electrode, such as indium tin oxide (ITO), Au/Si (151) and highly oriented pyrolytic graphite (HP(Xj) (152), the effective area of the electrode can be controlled by using a cell similar to that shown in Figure 13.8. The electrode surface exposed to the electrolyte solution containing a coreactant should face the window of the photo-detector. 

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